SAO PAULO (AP) — The right-wing front-runner in Brazil's presidential race called his leftist rival a "puppet" while his opponent mocked him for avoiding debates, engaging in a heated Twitter exchange Tuesday less than two weeks before their runoff election.

The candidates haven't met in any of a series of scheduled televised debates, with rightist Jair Bolsonaro declining to participate after being stabbed during a Sept. 6 campaign event. He was released from the hospital 23 days later but says his doctors recommended against him attending the debates.

In Tuesday's exchange, Bolsonaro called leftist candidate Fernando Haddad a "puppet guided by a drunkard" — a reference to jailed former President Luiz Inacio Lula da Silva, who hand-picked Haddad to succeed him as the Workers' Party presidential candidate after being barred from the race.

"It is easy to use Twitter and live online videos, congressman," responded Haddad, the former mayor of Sao Paulo. "Let's debate face to face, with politeness, in a hospital if needed. People need to see you coming to the job interview."

Bolsonaro won the first round of the presidential election Oct. 7 with 46 percent of the vote, against Haddad's 29 percent. But since he failed to top 50 percent, Bolsonaro is in a second-round ballot against Haddad on Oct. 28.

Tuesday's exchange began after Haddad criticized his own Workers' Party for recent corruption scandals, which include the huge "Car Wash" investigation that has ensnared Brazil's top political and business leaders.

Bolsonaro called his rival's acknowledgement of his party's mistakes "deceit" by "the puppet."

"The corruption in the Lula (da Silva) and Dilma Rousseff administrations was not isolated, it was a rule of governing," the former army captain tweeted.

Bolsonaro then tweeted: "There is one (drunkard) that was jailed for corruption, and you give him private visits every week." The far-right candidate used a term that describes conjugal visits by partners to male inmates.

Haddad retorted by criticizing Bolsonaro for staying away from the debates while still giving interviews and online speeches.

Haddad ended the Twitter exchange with a picture of a TV debate podium and the words: "I am waiting for you here, congressman."

Also on Tuesday, Haddad accused Bolsonaro of being endorsed by the Ku Klux Klan. A report by Britain's BBC said former KKK leader David Duke praised the far-right candidate and said he "sounds like one of us."

"My adversary is also meeting allies and gathering forces. Today he was endorsed by Ku Klux Klan," Haddad said.

Bolsonaro tweeted that he refuses any support coming from supremacist groups. Brazilian supremacist groups have applauded his candidacy.

"I suggest that ... they support my adversary, the candidate of the left who loves to segregate society," Bolsonaro said.

Bolsonaro has repeatedly defended Brazil's 1964-1985 military dictatorship and made comments deemed offensive to gays, minorities and women.

His words with Haddad came as the Workers' Party criticized the other candidates defeated in the first round of voting for not uniting behind Haddad against Bolsonaro.

Party chairwoman Gleisi Hoffmann took to Twitter after a poll released Monday put Bolsonaro far ahead of Haddad.

"If the Workers' Party were not in the runoff, it would endorse the adversary of congressman Bolsonaro because he will not promote democracy in this country," Hoffmann tweeted. "We hoped that this was going to be a natural move (to endorse Haddad), but I am seeing it is not."

"In the future history will judge us all," she said.

The only defeated presidential candidate who has endorsed Haddad is leftist Guilherme Boulos, who had minimal support in the opening round.